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Prevalence of anisometropia and its association with refractive error and amblyopia in preschool children
Sonia Afsari1, Kathryn A Rose, Glen A Gole
1Department of Ophthalmology, Westmead Millennium Institute, Centre for Vision Research, University of Sydney, New South Wales, Australia.
Insights
Anisometropia is uncommon in Australian preschoolers, with variations across ethnicities. Higher levels of refractive error significantly increase the risk of anisometropia and amblyopia.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Public Health
Background:
- Anisometropia, a refractive error disparity between eyes, affects visual development in children.
- Understanding its prevalence and associated risks is crucial for early intervention.
Purpose of the Study:
- To determine the prevalence of anisometropia in Australian preschool children based on age and ethnicity.
- To assess the risk of anisometropia with increasing ametropia and the risk of amblyopia with increasing anisometropia.
Main Methods:
- A population-based study of 2090 children (6-72 months) in Sydney.
- Cycloplegic refraction using autorefractors and retinoscopy.
- Anisometropia defined by spherical equivalent (SE) and cylindrical differences.
Main Results:
- Overall prevalence of SE and cylindrical anisometropia ≥1.0 D was 2.7% and 3.0%.
- Prevalence varied by ethnicity, with East-Asian children showing higher cylindrical anisometropia (5.2%).
- Significant risk of anisometropic amblyopia (OR 12.4 for SE, 6.5 for cylindrical). Increased risk of anisometropia with myopia (OR 61.6), hyperopia (OR 13.6), and astigmatism (OR 30.0).
Conclusions:
- Anisometropia is uncommon in Australian preschoolers, with notable ethnic variations in cylindrical anisometropia.
- Quantified the substantial increase in amblyopia risk with higher levels of SE and cylindrical anisometropia.
- Established specific refractive error thresholds associated with increased anisometropia risk.
Aim:
To determine the age and ethnicity-specific prevalence of anisometropia in Australian preschool-aged children and to assess in this population-based study the risk of anisometropia with increasing ametropia levels and risk of amblyopia with increasing anisometropia.
Methods:
A total 2090 children (aged 6-72 months) completed detailed eye examinations in the Sydney Paediatric Eye Disease Study, including cycloplegic refraction, and were included. Refraction was measured using a Canon RK-F1 autorefractor, streak retinoscopy and/or the Retinomax K-Plus 2 autorefractor. Anisometropia was defined by the spherical equivalent (SE) difference, and plus cylinder difference for any cylindrical axis between eyes.
Results:
The overall prevalence of SE and cylindrical anisometropia ≥1.0 D were 2.7% and 3.0%, for the overall sample and in children of European-Caucasian ethnicity, 3.2%, 1.9%; East-Asian 1.7%, 5.2%; South-Asian 2.5%, 3.6%; Middle-Eastern ethnicities 2.2%, 3.3%, respectively. Anisometropia prevalence was lower or similar to that in the Baltimore Pediatric Eye Disease Study, Multi-Ethnic Pediatric Eye Disease Study and the Strabismus, Amblyopia and Refractive error in Singapore study. Risk (OR) of anisometropic amblyopia with ≥1.0 D of SE and cylindrical anisometropia was 12.4 (CI 4.0 to 38.4) and 6.5 (CI 2.3 to 18.7), respectively. We found an increasing risk of anisometropia with higher myopia ≥-1.0 D, OR 61.6 (CI 21.3 to 308), hyperopia > +2.0 D, OR 13.6 (CI 2.9 to 63.6) and astigmatism ≥1.5 D, OR 30.0 (CI 14.5 to 58.1).
Conclusions:
In this preschool-age population-based sample, anisometropia was uncommon with inter-ethnic differences in cylindrical anisometropia prevalence. We also quantified the rising risk of amblyopia with increasing SE and cylindrical anisometropia, and present the specific levels of refractive error and associated increasing risk of anisometropia.
